This invention is directed to security or jail cell construction for use in existing or new buildings. More particular, the invention is related to a modular wall and ceiling system manufactured of substantially similar prefabricated units or panels and a method of assemblying the units into a cell structure. The structure is for particular use as a speedily erected temporary or permanent prison housing, although the invention could have applicability to other uses where the concepts of the construction would warrant. The problem that this invention overcomes is accomplishing the construction where there is limited space usually adjacent existing walls.